In addition to vibrator supplies, another method of getting plate voltage for tubes in mobile applications was a device called a dynamotor.
Looked like a small electric motor, with no external shaft. Inside, it consisted of a low voltage DC motor and a high voltage DC generator on a common shaft. Almost as noisy as a vibrator supply electrically (and mechanically they sounded like a jet engine winding up !), but they did away with the need for rectifying the output voltage.
Some SSB ham transcievers (Heathkit and Collins for sure, probably others) of the late tube era had transistorized mobile power supplies available as options. A separate box that would convert 12VDC into 800VDC for the final tubes, as well as various bias voltages, etc.
